Direct patterning of nitrogen-doped CVD graphene based microstructures for charge carrier measurements employing femtosecond laser ablation

Abstract

Chemical vapor deposited nitrogen-doped graphene, transferred on SiO2/Si substrate was selectively patterned by femtosecond laser ablation for formation of the topology dedicated for charge carrier measurements. Ultrashort 1030 nm wavelength Yb:KGW fs-laser pulses of 22 μJ energy,14 mJ/cm2 fluence, 96% pulse overlap and scanning speed of 100 mm/s were found to be optimum regime for the high throughput microstructure ablation in graphene, without surface damage of the substrate in the employed fs-laser micromachining workstation. Optical scanning electron, atomic force microscopy as well as Raman spectroscopy were applied to clarify the intensive fs-laser light irradiation effects on graphene and substrate as well as to verify the quality of the graphene removal. Measurements of magnetotransport properties of the fs-laser ablated nitrogen-doped graphene microstructure in the Hall configuration enabled determination of the type as well as concentration of charge carriers in a wide temperature range.